A technique has been proposed to drive and rotate front and rear wheels of a vehicle separately by two rotating electrical machines. For example, JP-A-2003-32802 discloses a four-wheel-drive hybrid vehicle in which a motor MG3 drives and rotates front wheels and a motor MG2 drives and rotates rear wheels. The motors MG2, MG3 are controlled by a control apparatus mounted on the vehicle.
In the control apparatus disclosed in JP-A-2003-32802, a request torque is divided between the motor MG2 and the motor MG3. At this time, a torque division ratio is set so that the amount of torque distributed to the motor MG3 can be greater than the amount of torque distributed to the motor MG2. Further, a power distribution ratio in which electrical power of a battery is distributed between the motors is set equal to the torque division ratio because the rotation speeds of the front and rear wheels are equal to each other.
In a vehicle having the control apparatus disclosed in JP-A-2003-32802, torque of the motor MG3 may be limited due to heat, and the supply of electrical power to the motor MG2 may be limited depending on the remaining power of the battery. In this case, the motor MG2 and the motor MG3 may be unable to output torques according to command torques. Specifically, although the motor MG3 can be supplied with electrical power enough to output the command torque, the motor MG3 may be unable to output the command torque due to heat. That is, the motor MG3 is supplied with the amount of electrical power the motor MG3 is expected to be unable to consume. In contrast, since the motor MG2 may lack electrical power due to short of the remaining power of the battery, the motor MG2 may be unable to output the command torque.